Traffic lines are an accepted device in the field of traffic safety. The earliest traffic lines were put into use by Edward N. Hines on Trenton's River Road in Wayne County, Mich. Later refinements led to single and double lines, broken lines located in the center of the roadway and along the edges.
Traffic lines can be painted with a basic permanent paint that is optimally visible only under the best illumination. Given that roadways are travelled by day and night, in conditions of clear weather, fog, snow, sleet, smoke or other visual impairments. Under these circumstances, the paint can become invisible and increase the risks to the traveler. Furthermore, even the stoutest paint can be rubbed off the road surface by plow trucks, sand and other causes. Roadway engineers have determined that thermoplastic paints last longer than common paint and that the addition of small glass beads to the mixture creates a reflective surface that increases visibility under inclement conditions and at night. A concentration of glass beads in the paint mixture at a ratio of six pounds of beads per gallon of paint, according to current standards within the various states. This creates a heterogenous mixture. Thermoplastic traffic paint is generally applied in two coats, each of 60 mil thickness. The colors used are white and yellow. The thermoplastic paint is applied hot by spraying of extruded as a ribbon and is 4 inches in width. The glass beads are added while the mixture is still molten hot. The mixture starts as a homogenous dry mix of binder resins, plasticizers, glass beads (or similar material bead), pigments and fillers. The mixture is heated to approximately 400 degrees Fahrenheit and placed into the dispenser, which is mounted on a vehicle or a small “walk behind” manually operated device. The lines can be uniform on their upper surface or embossed with diamond or other patterns to increase reflectivity. The application of a binding agent prior to the application of the traffic line material can improve the longevity of the traffic lines.
The visibility of traffic lines remains a problem for travelers. The lines tend to be elongated ribbons of reflective material when viewed from the driver's seat. Over time, the traveler's visual acuity can degrade from fatigue and the homogeneity of the elongated lines lose their relevance, increasing the risk to the driver. FIG. 1 is a view of a roadway 100 provided with traffic lines 102 and a truck 104 that is driving with the assistance of its headlights 106 and their cast beams 108. The extent of the driver's optimal visibility is represented by broken line 110. The lines 102 are evenly spaced and stretch off into the gloom and darkness, disappearing beyond the optimal visibility extent 110. It would be desirable to provide a traffic line that is reflective and constructed and arranged to be visually stimulating and maintain the interest of the driver, thereby increasing highway safety.